1. Field of the Invention
The present invention relates to a technique of controlling a plurality of printing devices.
2. Description of the Related Art
A printing system, in which a plurality of personal computers and a plurality of printers are connected together via a network, such as a LAN (Local Area Network), has been widely used. As a recent trend, further technique that causes a print server to distribute print jobs to a plurality of printers connected with the network, what is called distributed printing, has become common. This distributed printing enables parallel printing processing of a number of print jobs with the plurality of printers, and thereby reduces the total time required to the printing.
Image data, which is input in the printer as a print job, typically includes tone data expressed in a color system of R (Red), G (Green) and B (Blue). The printer carries out the printing by converting the tone data expressed in this RGB color system into the tone data in the color system of C (Cyan), M (Magenta) and Y (Yellow).
In some applications, however, even a plurality of color printers of the same type causes color distinction among resulting prints one another in carrying out the printing of a uniform color image through the same process. In the case of using an ink jet printer, such distinction results from, for example, an error of ink discharge quantity by a print head. It is substantially hard to control the above-mentioned distinction among resulting prints by performing perfect calibration at the time of manufacture of the printer.
Those problems regarding the distinction in resulting prints caused by the difference among printers may arise in black-and-white printers as well as in color printers. These problems are not restricted to ink jet printers, but similar problems arise in other types of printers.